The aortic valve area is located craniodorsal to the left apex and the second heart sound is best heard there. A useful clinical pointer is to first palpate the left apex beat where mitral sounds radiate and the first heart sound is best heard. 4, 5 While the exact anatomic location of the valve areas depends on the species, chest conformation, and size of the heart, a common relative location is found from cranial to caudal: pulmonic-aortic-tricuspid-mitral with the tricuspid valve on the right. The entire precordium is examined, with particular attention directed to the cardiac valve areas. Excessive pressure on the chest can distort the thorax of small animals and create murmurs.
#Sibilant rhonchi lung sounds skin
These include synchronous ventilation and panting (which can mimic murmurs) skin twitching (creating extra heart sounds) and friction from rubbing the chest piece across hair (sounding like pulmonary crackles or "rales"). Sound artifacts may be misinterpreted as abnormal heart or lung sounds. Showing the feline patient water in a sink, picking up the cat, or gently pressing over the larynx may reduce the degree of purring. Gently holding the mouth closed, whistling, or briefly obstructing the nares are effective maneuvers for reducing ventilation artifacts.
The patient must be calm and ventilation and purring controlled if possible. A cat can be gently restrained with one hand under the abdomen this encourages the cat to stand on the forelimbs. It is preferable for the animal to stand in order to locate the valve areas accurately. The room must be quiet, the patient gently restrained, and the examiner relaxed. The bell is also useful for detection of the more uncommon diastolic murmurs.Ĭonditions for auscultation are often overlooked but substantially impact the results of the examination.
The bell, which is applied lightly to achieve an airtight seal, enhances detection of lower frequency sounds such as the third and fourth heart sounds. The flat diaphragm chest piece is applied gently but firmly to the chest to accentuate higher frequency sounds such as normal heart and breath sounds and most cardiac murmurs. The stethoscope tube length should not be excessively long, the binaurals and ear pieces should be directed so that their orientation is rostral and aligned with the ear canals, and earpieces should be inserted snugly but comfortably to obtain an airtight seal. The clinician must understand that many heart sounds fall below the frequency-threshold limit accordingly, careful auscultation is necessary to detect the vibrations that are audible. Some of the newer models, such as the Welch Allen Meditron®, are accurate and also can provide an instructive computer printout of recorded sounds along with an ECG for timing purposes. Amplified stethoscopes generally are not recommended because of the potential for blooming artifacts and distortion however, they can be useful for those with a hearing impairment. However, some of the newer models combine both "adult" and "pediatric" single chest piece stethoscopes into one rotating head. While acoustically superior in some ways, the single chest piece design of some adult stethoscopes is too large for cats and small dogs. Some stethoscope designs allow a single chest piece to function as both a bell and a diaphragm. The traditional stethoscope has an operator selected diaphragm and bell. The choice of a stethoscope is very personal. The essential abnormalities of cardiac auscultation include: abnormal heart rate (bradycardia, tachycardia) irregular cardiac cadence or rhythm abnormal intensity of heart sounds extra heart sounds absent sounds split sounds cardiac murmurs and pericardial friction rubs.
This presumption can then be confirmed, refined, or refuted by echocardiography (for valvular disease, pericardial disease, cardiomyopathy, or shunts) or by electrocardiography (for arrhythmias). Often the combination of signalment, cardiac and pulmonary auscultation, and general physical examination point to a tentative cardiac diagnosis. Definitive diagnosis may be possible by auscultation, as when classic murmurs of patent ductus arteriosus or mitral regurgitation are identified. When completed by an experienced clinician, auscultation carries a high predictive value for identification of many-though not all-serious heart diseases. The auscultatory exam is expedient and cost effective. Books & VINcyclopedia of Diseases (Formerly Associate)Īuscultation of the heart remains an important examination for the detection of cardiovascular disease.VINcyclopedia of Diseases (Formerly Associate).
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